Add a custom label on the right on UITableViewCell

TableViewControllerRightLabelCell.swift

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cellIdentifier = "CellIdentifier"
        let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) ?? UITableViewCell(style: .value1, reuseIdentifier: cellIdentifier)

        let label = UILabel()
        label.textAlignment = .right
        label.backgroundColor = UIColor.clear
        label.textColor = UIColor.gray
        label.translatesAutoresizingMaskIntoConstraints = false
        cell.detailTextLabel?.text = "TEST"

        cell.addSubview(label)
        label.trailingAnchor.constraint(equalTo: cell.trailingAnchor, constant: -30.0).isActive = true
        label.centerYAnchor.constraint(equalTo: cell.centerYAnchor, constant: 0).isActive = true

        cell.textLabel?.text = "indexPath.row \(indexPath.row)"
        return cell
    }